Widely known gaming devices have three to five rotatable reels arranged side by side with symbols, such as a lemon, cherry, bar, or the like placed on the peripheral surface thereof. There are also gaming machines which employ video displays in lieu of physical reels. In both the mechanical and video type gaming devices, a player inserts a token representing a value. The token may be coin, currency or the like. For convenience, all such tokens are referred to herein as simply "coins". The player then causes the reels to spin by pulling a handle located on the side of the machine or in some cases pressing a button. After a predetermined length of time, the reels are stopped to display the symbols. A determination is made as to whether the combination of displayed symbols matches a predetermined combination. If such a match occurs, the machine pays out a number of tokens in accordance with a predetermined payout amount which relates to the odds that the particular combination would occur.
Advances in gaming machine technology and in particular with respect to microprocessor controlled slot or reel type machines have made it possible to have variable payouts relative to the value of a coin input. For example, U.S. Pat. No. 4,624,459 discloses a machine capable of making multiple payouts at random intervals. Additionally, the virtual reel concept as disclosed in U.S. Pat. Nos. 4,448,419 and 4,711,451 has resulted in machines which have a maximum payout many thousands of times the value of the coin input.
It has been observed that players are more apt to play gaming machines for longer periods of time if the payout (and odds of winning) are increased as the player continues to play that particular machine. Further, players are more apt to insert additional coins if they perceive some continuing value from coins already expended.